1 /* 2 * OMAP4 SMP cpu-hotplug support 3 * 4 * Copyright (C) 2010 Texas Instruments, Inc. 5 * Author: 6 * Santosh Shilimkar <santosh.shilimkar@ti.com> 7 * 8 * Platform file needed for the OMAP4 SMP. This file is based on arm 9 * realview smp platform. 10 * Copyright (c) 2002 ARM Limited. 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/errno.h> 19 #include <linux/smp.h> 20 #include <linux/completion.h> 21 22 #include <asm/cacheflush.h> 23 #include <mach/omap4-common.h> 24 25 static DECLARE_COMPLETION(cpu_killed); 26 27 int platform_cpu_kill(unsigned int cpu) 28 { 29 return wait_for_completion_timeout(&cpu_killed, 5000); 30 } 31 32 /* 33 * platform-specific code to shutdown a CPU 34 * Called with IRQs disabled 35 */ 36 void platform_cpu_die(unsigned int cpu) 37 { 38 unsigned int this_cpu = hard_smp_processor_id(); 39 40 if (cpu != this_cpu) { 41 pr_crit("platform_cpu_die running on %u, should be %u\n", 42 this_cpu, cpu); 43 BUG(); 44 } 45 pr_notice("CPU%u: shutdown\n", cpu); 46 complete(&cpu_killed); 47 flush_cache_all(); 48 dsb(); 49 50 /* 51 * we're ready for shutdown now, so do it 52 */ 53 if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0) 54 printk(KERN_CRIT "Secure clear status failed\n"); 55 56 for (;;) { 57 /* 58 * Execute WFI 59 */ 60 do_wfi(); 61 62 if (omap_read_auxcoreboot0() == cpu) { 63 /* 64 * OK, proper wakeup, we're done 65 */ 66 break; 67 } 68 pr_debug("CPU%u: spurious wakeup call\n", cpu); 69 } 70 } 71 72 int platform_cpu_disable(unsigned int cpu) 73 { 74 /* 75 * we don't allow CPU 0 to be shutdown (it is still too special 76 * e.g. clock tick interrupts) 77 */ 78 return cpu == 0 ? -EPERM : 0; 79 } 80